I don’t have any good suggestions, but I have two questions that might be relevant to you or to other people who do have ideas.
Will you be visiting a grocery store in Iceland to get your ingredients? Or will you be packing them in your luggage on the flight over?
If they are in your luggage, will there be any customs tomfoolery if you’re bringing lots of food with you? (I have never flown with lots of food in my luggage; I have no idea if this is even a concern, but wanted to bring the question up in case it is.)